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首页> 外文期刊>The Astrophysical journal >DETAILED SPECTRAL ANALYSIS OF THE TYPE Ib SUPERNOVA 1999dn. I. HYDROGEN-FREE MODELS
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DETAILED SPECTRAL ANALYSIS OF THE TYPE Ib SUPERNOVA 1999dn. I. HYDROGEN-FREE MODELS

机译:Ib SUPERNOVA 1999dn型的详细光谱分析。 I.无氢模型

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摘要

We present spectral fits to five epochs of the typical Type Ib supernova 1999dn using the generalized, non-LTE, stellar atmospheres code PHOENIX. Our goal is threefold: to determine basic physical properties of the supernova ejecta, such as velocity, temperature, and density gradients; to reproduce He I absorption lines by invoking nonther-raal excitation; and to investigate possible spectral signatures of hydrogen, especially a feature around 6200 A, which has been attributed to high-velocity Ha. Our models assume an atmosphere with uniform composition devoid of any hydrogen. Our model spectra fit the observed spectra well, successfully reproducing most of the features, including the prominent He I absorptions. The most plausible alternative to Ha as the source of the 6200 A feature is a blend of Fe n and Si ii lines, which can be made stronger in order to better fit the observed feature by increasing the metallicity of the ejecta. High-metallicity models fit well at early epochs, but not as well as solar-metallicity models after maximum light. While this blend of metal lines is a reasonable explanation of the source of the 6200 A feature, it is still important to investigate hydrogen as the source; therefore, a second paper will present models that include a thin shell of hydrogen around the main composition structure.
机译:我们使用广义的非LTE星体大气代码PHOENIX对典型Ib型超新星1999dn的五个纪元进行光谱拟合。我们的目标是三重的:确定超新星喷射的基本物理特性,例如速度,温度和密度梯度;通过激发非种族激发来复制He I吸收谱线;并研究氢的可能光谱特征,尤其是6200 A附近的特征,这归因于高速Ha。我们的模型假设气氛均匀且不含氢。我们的模型光谱与观察到的光谱非常吻合,成功地再现了大多数特征,包括突出的He I吸收。作为6200 A特征的来源,最可能替代Ha的是Fe n和Si ii线的混合物,可以使其更牢固,以便通过增加喷射的金属性来更好地适应观察到的特征。高金属性模型很适合早期时代,但不如最大光度后的太阳金属性模型好。虽然这种金属线的混合可以合理地解释6200 A功能的来源,但研究氢作为来源仍然很重要。因此,第二篇论文将提出模型,该模型包括围绕主要成分结构的氢薄壳。

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